[cairo] Drawing text with different glyph widths

[Jeff Muizelaar]

PDF documents often do not embed fonts, however they do include the
glyph widths for the missing fonts. Currently, the poppler cairo backend
ignores these widths and draws the text with the glyph widths of the
substituted font. This often causes some very ugly rendering:
https://bugs.freedesktop.org/show_bug.cgi?id=12304
https://bugs.freedesktop.org/show_bug.cgi?id=11864

To fix these we need to draw using the glyph widths specified in the pdf
file. Does anyone have any suggestions for how to achieve this with
cairo?

-Jeff